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junek
29th August 2005, 12:50 PM
i was just doing a geocache and was standing in a very exposed spot on a ridge and noticed my magellan 500 said 5meter accuracy and was picking up WAAS.
it has never done this before
anyone know why it would be saying WAAS, i was lead to believe it was not available in aus
jamie

festy
29th August 2005, 02:40 PM
As far as I know, it's not available in Australia and there aren't any plans to implement it here. WAAS is a series of about 25 ground stations around the US - I doubt you'd pick up their signal here :)
There are a few mobs doing LAAS (limited area) in oz - I've heard that CSIRO have been working on a system that gives amazing resolution, but requires base stations a very short distance apart.
You should be able to get 5m accuracy without waas anyway with a good view of the sky.

What area were you in?

leelee2830
29th August 2005, 05:30 PM
There is a WASS sat. positioned over India I have been told. My magellan usually shows it's position low in the north west sector of the sat. availability screen.

arthurking83
29th August 2005, 06:30 PM
My understanding of WAAS is that there are ground stations that communicate with WAAS sats. The info recieved by the WAAS sat from the ground stations is then relayed to a GPSr to give a higher resolution fix.
That's a very simplistic version (of my understanding).
So!
If you were far enough to the north and the sat over India is high enough to be visible on the horizon, then you will just get a weak WAAS fix.
The problem is that the distances involved from ground station to sat and to GPSr will make that fix inaccurate. Best advice for Aussie GPSes, is to disable WAAS, and maybe save some battery power!

Next time you get the WAAS sat, find out its PRN number!

festy
29th August 2005, 07:01 PM
My earlier description of the waas system was a bit off. There are base stations that transmit the correction signal to a central point, which transmits a signal to the WAAS sats , which rebroadcast to the GPSrs. These sats are geostationary, unlike the regular GPS sats. Although you might be able to recieve a signal from one, it won't have any meaningful correctional data for you . There's tonnes of information on the net about how WAAS works, the location of the sats and ground stations etc.

strider01
29th August 2005, 08:18 PM
From a training course I did last year in GPS, I was told that WAAS was not available in Oz. In fact we were told to disable it in the units as I'm sure they said it would decrease accuracy here. Not sure about the last bit but we definitely told to disable it.

junek
2nd September 2005, 05:54 PM
ahhhhhhh, ok, just as i thought.
dont know why the gps had WAAS on the screen as i was in sydney.?
thanks strider1, i'll turn it off.
and yes, the 500 will say 5 to 6 meter accuracy on the screen, but i reality, it will take me to within 1.5 of a cache
thanks guys
jamie

Dooghan
2nd September 2005, 10:14 PM
There has been a big discussion about this over at Geocaching Australia forum. I would seem that a new WADGPS satellite (129 - MTSTAT1R sitting just north of PNG E140) launched in Feb 2005 is the problem. It would seem the Japanese are testing it at the moment. As WADGPS is supposedly compatibe with WAAS, the GPS is confusing it as a WAAS signal. As we don't have WAAS in Australia the data from this sat is no good to us. So just disable WAAS on your GPS. Saves it from processing data it can not use.

Dooghan

junek
3rd September 2005, 09:26 AM
whats the australian geocaching forum?? like to find that...




UPDATE: found it.

The Explorer
10th September 2005, 04:18 PM
http://geocaching.com.au/

Cheers
Greg

Daveosgps
14th September 2005, 08:38 PM
Hi

Do all the later model GPS have the WAAS function? and if so is this mainly because they are manufactured overseas? where the WAAS can be used.

cheers dave

arthurking83
14th September 2005, 09:22 PM
Hi

Do all the later model GPS have the WAAS function? and if so is this mainly because they are manufactured overseas? where the WAAS can be used.

cheers dave

I think....yes, and what you have to remember is that GPS is a GLOBAL positioning system!! :D
Invented??(made operational) by the Yanks. The US government, in their wisdom, decided that civillians needed more accuracy, hence WAAS. But apparently WAAS is not without some problems (to do with timing/atmosperic conditions??) and there is a new GPS system coming online soon, by the Europeans, called EGNOS. Google it for more info.
There are some really new GPSr's (Magellan - explorist, Garmin - ??)that can use the EGNOS signal (they will provide more accuracy!)

There you go! more GPS stuff to learn about :D

Daveosgps
14th September 2005, 09:33 PM
Hi Arthur

thanks again for you reply. Do you think the EGNOS will be usable here in Aus? if it is it may well be worth looking into the models that have it. In the mean time I will check it out on google as you suggest.

cheers dave

arthurking83
14th September 2005, 10:20 PM
My understanding of EGNOS, is that it's supplemental to and backward compatible with GPS. (??)

That means that there will be something like 50 or more satellites in the sky! That'll give better performance through less time with only 4 sats!

ps: I'm currently watching my Meridian recieve some 'bogus' WAAS signal??
It's locked onto 2 WAAS sats, but my info is that they are not really WAAS sats, and are only part of a satellite test (future WAAS/EGNOS service in Aus??)

EGNOS capable GPS's?? I don't know?
The system should be online in 2007-8?? get the best device that suits your needs NOW!
Worry about the future, in the future?? if that makes sense :confused:

eg. Lets say you decide to get an Explorist (which is EGNOS capable) instead of an Etrex legend.
You decide to go out prospecting in Abakangaroola :D
There's no power, no water, etc...you gotta be totally self sufficient!
Did you realise that the Explorist is rechargeable by it's own re-charger? did you bring it along?
The Garmin runs on AA's, but as you already have AA's to power your camera, discman, etc....
(that was only a hypothetical situation..I'm not suggesting you're disorganised.... :p )
The point being made is... get all the info on what limitations each unit has, then look at the features it has (they all basically have similar features)!
This way you will be more likely to be happy!

Daveosgps
15th September 2005, 06:52 AM
Hi Arthur

Excellent advice I'll use as I am researching the best GPS for my needs & budget.

cheers dave

arthurking83
16th September 2005, 10:28 PM
Temptation got the better of me yesterday, and I had to run with WAAS enabled all day!

What I found! As others have stated "Turn it off/Disable it"

DON'T USE WAAS!!

Now it wasn't such a big deal, but it did make it harder for the MeriColor to get a fix in "The City".
Definition of "The City"??... 5° view of the sky between 87.5° and 92.5° from the vertical :D

seriously, the MeriColor holds onto those sats kind of tenaciously, while driving through the city, only having a hard time if I've gone undercover, and re-emerged after 5-10 mins. It can take upto 3 mins to lock onto 3 birds!
If I use the CityLink tunnel, after the exit it will lock on within 100 meters or 2-3 seconds. With a narrow view of the sky (10+ story buildings along a narrow lane) it will struggle.
With WAAS on, there's no hope!
I gave up after 5 mins, and drove to a more open area! Ah that's better!

On startup in the morning, it took at least 5 minutes to get an accurate fix, and the resulting track was crazy! (I'm fairly certain I didn't drive through those houses??) :D
In general the track followed the road almost perfectly, as usual, but it did lose lock (wander) more often (twice as opposed to never!)

Considering the negatives, heed the advice of the experts! Turn it off.
If you don't know how, ask!
If you haven't, (I'm certain that Magellans are WAAS enabled by default??)
do so ;)

but the interesting info I found with those WAAS birds.
There were two sats I found locking on, PRN129 and PRN134,

From Geocaching aus:

129 is MTSTAT1R which was launched Feb 2005, sits just north of PNG at 140E.
This is NOT a WAAS satellite, although it is a new WADGPS satellite.

PRN 134 is the Pacific Ocean Region sat (Inmarsat3F3) also known to Garmins as #47.

Here's (http://gpsinformation.net/exe/waas.html) some WAAS info for those who need to know.

In fact all you need to know......"Turn it off!" :D

Pajerobitz
4th October 2005, 07:49 PM
I have picked up waas tonight 04 ,20(# of the sat on my magellan gold
total sats online at the moment 8

arthurking83
4th October 2005, 08:20 PM
I have picked up waas tonight 04 ,20(# of the sat on my magellan gold
total sats online at the moment 8

That's weird, my Meridian(color) only shows the WAAS sats as "W" only. No numbers?!?!

Nicko
18th October 2005, 10:00 AM
Nice snippet of info Dooghan

PED04
22nd October 2005, 08:57 PM
I suspect the problem with using WAAS in Aust is that they don't actually have the proper local correction information (such as correction for atmospheric conditions) for Australia, even though they can be picked up. So instead of making it more accurate, it may throw it out more.

michaeld
23rd October 2005, 11:56 AM
how do you turn off waas

Dooghan
23rd October 2005, 01:44 PM
how do you turn off waasThat would depend on the GPS you are using. You will have to tell us what GPS you are using before we can help you.

michaeld
23rd October 2005, 08:40 PM
sorry explorist 600

nosnevets
2nd November 2005, 09:50 PM
From a training course I did last year in GPS, I was told that WAAS was not available in Oz. In fact we were told to disable it in the units as I'm sure they said it would decrease accuracy here. Not sure about the last bit but we definitely told to disable it.
Hi Strider as a new starter, where did you get a GPS course?

Nicko
3rd November 2005, 02:48 PM
WAAS is switched off by default by Magellan and Garmin. In the setup page is the option to turn off WAAS. Where speicifically I do not know buthave a look around.

arthurking83
3rd November 2005, 05:43 PM
I think WAAS may be on by default on Magellans(??)

To turn it off, you can access the secret menus....

With the unit off, press and hold the [Nav] button while pressing the [Pwr] button.
This should bring up a box with two digits (possibly zeros).
Use the arrow keypad change the digits to [03] and press enter.
This should bring up the WAAS Sat status screen, and there should be an indication that WAAS is ON.
Press enter and this should change it to OFF.

Power down the unit and now WAAS should be OFF!

hope this helps!

kay dee exer
3rd November 2005, 10:04 PM
Thanks Arthur. My ex500 went from getting no lock inside my bedroom to tracking 6... Great tip... :D

arthurking83
4th November 2005, 06:11 AM
Apparently saves on power too! (??) :confused:

GU2
7th November 2005, 12:11 PM
Thanks, it works on MAGELLAN GOLD as well.

arthurking83
7th November 2005, 03:23 PM
Thanks, it works on MAGELLAN GOLD as well.

Yep! I have a Meridian Color.

It seems that the Explorist and Meridian have some similar "secret menu" functions.

arthurking83
5th December 2005, 04:36 PM
Small update.....................

I've been reading up about information (unconfirmed!!) that there may be a WAAS type of base station under testing in the Canberra area :confused:

I still don't believe it fully, (but it would be nice if true).

I've had my MeriColor on WAAS enabled....
{You can do this quickly with Meridians by pressing the [Menu] button then press the right, left, right, left arrows to get the secret menu and change the [00] to [03] and [Enter].
If WAAS is on, then you will see three boxes with "On" and at the top of the screen 2 WAAS sat status info boxes. Pressing [Enter] will alternate between On and Off}

For the first day or so it wouldn't lock onto the W sat consistently!!
But now, it seems to hold onto that W sat much better.

More importantly while I sit at my desk with the WAAS enabled Meridian, there is much less (usually zero!) "drift" or wander on the GPS track!
ie. it seems more accurate when it has a good lock onto the WAAS sat (which we all know isn't really a WAAS sat!)

In Melbourne I get SAT # 137 at Elevation 46, Azimuth 352, SNR about 40-55.
(can't get a lock at all on #129)

So that makes me "less sceptical" about the rumored Canberra "WAAS" station!

Any more info would on this would be great!!

Cheers.

arthurking83
5th December 2005, 08:25 PM
I justy finished reading a lot of PDF's about the "problem" MTSAT giving us WAAS signals!

It seems that the MTSAT-1R is fully operational as of 28-June-05.
MTSAT-2 is due to be commisioned in 2006 (even though it's up there!)
PRN129 is MTSAT-1R as Dooghan stated earlier, and MTSAT-2 is going to be PRN137.
(this is how Magellan GPSr sees them, Garmins will be different!)

They are basically side be side, PRN129 @ 140°E and PRN @ 140°±5°.

They both have the ability to send each others signal, so that in the event of a failure from one sat the other will send the signal.
Either way we will recieve both satellites' signal, even if it's only coming from one bird! (Redundancy!)


To provide MSAS service over Japanese FIR, four ground monitor stations (GMSs) are
installed at each air route traffic control centre (ARTCC); Sapporo, Tokyo, Fukuoka and Naha. To secure
long base line for accurate orbit determination of MTSATs, two monitor and ranging stations (MRSs) are
installed in Hawaii, United States and Canberra, Australia. There is also MRS at each aeronautical satellite
centre. MRSs also have the function of GPS monitoring just like GMS. Each of GMS and MRS is connected
with two MCSs by dedicated ground lines and sends received GPS/MSAS signals. MCSs generate the
augmentation information for GPS using the received data from GMSs and MRSs, and uplink to MTSAT
through ground earth stations (GESs). There are eight monitoring stations in total for GPS/MSAS signal
reception.

I'm translating that as "WE HAVE WAAS!!"

Now!
....We don't have the US WAAS system, but the Japanese version called MSAS.
They are all interoperable (including EGNOS)
They are all SBAS (Space Based Augmentation Systems)
So call it WAAAS, MSAS, or SBAS, it all means the same thing.

(From here on I'm calling it MSAS!!)

And we have it operating here in Aus (thanks to the Japanese!)
Does this mean more accurate position data.
While looking for more info I came across a site that (in summary) said....

You need to get a lock(even if only briefly and intermittently) onto one of the MSAS sats!!
This will download the required almanac into the GPSr for WAAS, (which is separate to the regular GPS almanac!
Then it will maintain a lock on the MSAS sat.

That explains what was happening to my GPSr when I said in my previous post....

For the first day or so it wouldn't lock onto the W sat consistently!!
But now, it seems to hold onto that W sat much better.
(But I still can't get my Meridian to lock onto #129)

It obviously updated the Almanac, and all is now sweet :D

Tip: Enable WAAS! ;)

cheers.

EDIT: I know you've had enough of my diatribe, but I loved this excerpt from the pdf....

Thus, the MSAS is fully interoperable with another SBAS services. That is, the United States
wide area augmentation system (WAAS) which has already started its operation on 10th July this year and
Europe’s European Geostationary Navigation Overlay Service (EGNOS) to be operated in 2004. No matter
where the aircrafts are flying in the world, the user avionics (SBAS receiver) can receive the SBAS signal
from WAAS, MSAS and EGNOS seamlessly on a global basis.

:D :D

The Explorer
5th December 2005, 08:47 PM
Hello
While the more accurate the better, for the average punter an increase in accuracy from 5 metres (normal handheld GPS with good sat fix) to 3m (WAAS accuracy) is not going to make a noticeble difference in most circumstances (eg when was the last time you missed a campsite, turnoff or could not find you car because your GPS was 2m out?). To tell you the truth I dont even know whey they have bothered doing it :confused: ..unless it will ultimately lead to 0m accuracy :D . Seems like a lot of work/money for little gain. Suppose someones having fun.
Cheers
Greg

arthurking83
5th December 2005, 09:07 PM
I think the main reason (for more accuracy) is not just the lower figures for distance, it also includes the amount of time that accuracy is available!

Also when averaging!
I'm sittinginfornt of the PC with the GPSr on, and logging with VisualGPS.
The small triangle cursor hasn't budged in over 6 hours.

I used to get wild variations of the GPSr wandering all over the state (and Country). But regularly I would see about .5km of track and odometer, after leaving it on all night and checking the next morning!

So accuracy in determining a point, like a property fence or whatever, (obviously not for professional use, just personal curiosity!)

And I think the average "WAAS Off" GPSr was capable of 7 meters, 95% of the time??
and <3 meters with WAAS enabled!

festy
6th December 2005, 05:24 AM
The extra accuracy will be welcomed by geocachers, where it makes a much beiiger difference than for general land navigation.

mitchofsutho
6th December 2005, 05:38 AM
No matter
where the aircrafts are flying in the world, the user avionics (SBAS receiver) can receive the SBAS signal
from WAAS, MSAS and EGNOS seamlessly on a global basis.

Based on the above quote arthurking provided from the PDF he refered to, which primarily related to aircraft, I wonder, with a greater number of perminent, known altitude, land based stations for satelites to talk to, if the new systems also provide a greater accuracy for altitude?

wombatwal
6th December 2005, 06:44 AM
I have a Garmin GPS60 and have turned on WAAS. Not sure if it is working though. The satellites are numbered from 3 to 33 but not all numbers are allocated a satellite. I have a number +or-5m or whatever on my screen which I assume is it's accuracy. The best I get is 5m. Anyone know how to check if WAAS or MSAS is working on a Garmin. Wombatwal

arthurking83
6th December 2005, 03:11 PM
I have a Garmin GPS60 ........... Anyone know how to check if WAAS or MSAS is working on a Garmin. Wombatwal

hi wombat,

Do you have a consistent lock on a high numbered sat?
From memory MSAS (or more correctly, SBAS) satellites have high, 40-50ish, numbers on Garmins?? (someone with a Garmin will confirm)

As I said previously, it may take some time for the (WAAS)almanac to fully load into the GPS. This is separate to the regular almanac.
I would let it settle for "up to 3 days!" with waas on.

I'll try to find that link to the "how to update the almanc", as it was based on using a Garmin GPSr..........



cheers.

festy
6th December 2005, 03:20 PM
I switched WAAS on this morning to see what I could see - I found MTSAT-1 (garmin #42) and MTSAT-2 (garmin #50), and have been getting the little 'D's on the signal strength page to show it's working. Best accuracy I've seen today was 4m, but with the lack of base stations in SE aus I wasn't expecting anything special.

toby25000
6th December 2005, 03:22 PM
hi arthur

I have just the basic extex and after reading your informative posts on waas I checked my unit but I don't think the garmin units have an on/off facility. I checked the garmin website and they list most of there product as waas enabled.

Not sure if they are factory set or you can switch them on or off.

Toby

festy
6th December 2005, 03:39 PM
I know the 'new' etrex yellow has waas off/on. On the 'Menu' page, go to Setup->System, GPS Mode. If your Etrex has a different menu layout, you're probably running the old style firmware.

I just had a bit more of a play with WAAS. With 8 sats + MTSAT-2 in view, I had a position accuracy of 5m, which occasionally flickered to 6m in 'normal' mode. As soon as I had 3 'D's, the accuracy was labelled as 'DIFF' and varied wildly between about 9m and 14m. It got down to 6m once for a second, before rising again. As soon as I lost one of the 'D's, the 'DIFF' dissapeared, and accuracy returned to 5m. I think a lack of base stations makes it pointless. There would need to be 20 or 30 to cover australia well enough to make it worthwhile.

I think I'll turn WAAS off again now.

toby25000
6th December 2005, 03:53 PM
Hi Festy

My extrex only has gps modes of normal, battery save or demo.

If I go to interface it has garmin, garmin dgps, nmea out, text out, rtcm in, rtcm/nmea, rtcm/text, none, of which I have only ever used garmin and nmea out. Not sure what the others do. They wouldn't have anything to do with WAAS would they?

Toby

festy
6th December 2005, 04:10 PM
I just checked my wife's Etrex, it has the same modes, plus WAAS in the menu. It's running firmware v3.30.

toby25000
6th December 2005, 04:38 PM
I just checked the garmin website for software upgrades and mine is up to date running v2.14. So there must be a more recent model yellow etrex than mine.

Thanks anyway.

Toby

arthurking83
7th December 2005, 07:02 PM
I'm a NOB :o

I found another pdf!

I'll link to it HERE (http://www.kasc.go.jp/MSAS/index_e.html) because it has good info on why to leave WAAS OFF

Summary:
MSAS siganls are a bit different to WAAS, in the data they supply to the GPSr.
The signal is only getting tested, there is a timetable as to when the signal is on and off.
(This timetable explains why I can't get a lock on a MSAS sat today!)

As Festy said........"I'll turn it off again"

I did read that Garmin intend to supply a EGNOS/MSAS firmware upgrade to it's GPSr's.
I'm not holding my breath for Magellan to do the same (for the Meridian) though!

BUT!!
My interpretation of the MSAS system is that we (at least the East Coast) in Aus should be able to benefit from the MSAS system (via the Canberra MRS station).

I don't know how the Central and Western states will fare though??

Oh well! Back to 15 meter accuracy then :(

wombatwal
7th December 2005, 07:13 PM
Artie, I have turned WAAS of as well. I could not locate let alone lock onto Satellites 42 or 50 for the Garmin anyway. :( Wombatwal

arthurking83
7th December 2005, 07:31 PM
Yeah I was getting great reception all day yesterday, and nothing all day today!

Have a look at the Future Transmission timetable.
Pick one of the "ON" dates to have your Garmin WAAS enabled, and see if you pick up the sat?? (may have to leave it on all day.....etc)

Interestingly.... a few people have mentioned that they get the MTSAT2 (PRN#137) reception, but MTSAT2 is due for launch in MAR-APR '06 !!

The Satellite is MTSAT-1r but the signal alternates for PRN129 and 137, but why not both at the same time??

I'll try again, just for some kicks!!

Apart from that..........roll on '07!!

Jackaroo
9th December 2005, 07:14 PM
Had the Etrex Legend on yesterday, during the time the Jap Sat was supposed to be active, but never had any sign of it over here in the west.

but
It was the first time I had seen 9 sats on the satellite screen with an accuracy of 4 metres. Once I lost the 9th Satellite, I was back to 5 metre accuracy

I suppose that is a bit better than the 15 metre accuracy Arthur gets. Must be the Garmin ;) ;)

arthurking83
9th December 2005, 08:22 PM
.......... I was back to 5 metre accuracy

I suppose that is a bit better than the 15 metre accuracy Arthur gets. Must be the Garmin ;) ;)

LOL! :D

Magellan quote from the manual......

7 meter accuracy 95% of the time,
and w/ WAAS <3 meter accuracy 95% of the time.

On the Meridian we don't get an estimated accuracy, like the Explorist do (and obviously some Garmins do too!)

phillipsart
18th March 2009, 07:49 PM
What's the latest on WAAS in Australia?

Should we have our GPS in WAAS mode?

Purchased a GPS book last week. Started reading it today, and read about WAAS. Mentioned in the Book with WAAS you get 2m and with out WAAS you get 15m accuracy. It don't make sense to me. I am confused. I don't have WAAS enabled on my Garmin Oregon 300 and it's telling me I am getting 2m accuracy. According to this book I purchased, that's not possible.

I gave it a go. I switched over to WAAS mode. GPS took longer to lock into Sat's. and it came up with 2m accuracy as I do without WAAS.

mlenser
18th March 2009, 07:55 PM
Don't enable WAAS in Australia as we have no local satellites that carry the correction information. I'm guessing your gps book is US and probably written before the US Military allowed the general public to have more accurate GPS information.

phillipsart
18th March 2009, 08:01 PM
Yes it is a US book.

Thanks for your help. I will disable WAAS. The book is dated back to 2003. I should have checked this before purchasing. Guy in shop told me this is a great book. He seamed to know what he was talking about, although he did not like Garmin. Told me to many models to choose from. I myself, thought that was a good thing.

Nicko
18th March 2009, 08:10 PM
Told me to many models to choose
:hysterica

phillipsart
18th March 2009, 08:32 PM
:hysterica

I had to really try hard to keep a straight face when he told me that. I felt like ROFLMAO.

Gold Coast got some strange people.

dugeem
18th March 2009, 11:34 PM
Don't enable WAAS in Australia as we have no local satellites that carry the correction information.

Actually the Japanese have two satellites in orbit which will be found by a WAAS enabled GPSr in Australia with a clear view of the Northern sky. Satellite IDs are 42 & 50.

Unfortunately the previous federal government declined to participate in the MSAS project and thus there are no ionospheric corrections available for Australia which makes the system not so useful.

In theory WAAS/MSAS also provides information on clock errors and satellite orbit deviations but these are typically far smaller infueunces on accuracy than ionospheric corrections.

Nicko
19th March 2009, 10:00 AM
FAQ on Transmission of MSAS Signal



Q1.Can my GPS receiver process the augmentation information transmitted by MSAS?

A1.Any GPS receiver not compatible with Satellite-Based Augmentation System (SBAS) such as the U.S. WAAS cannot process the augmentation information transmitted by MSAS. If the receiver is sold as "WAAS-compatible" or "WAAS-capable", the receiver may or may not process the information from MSAS.

Q2.Can a WAAS-capable receiver process the augmentation information transmitted by MSAS?

A2.A WAAS-capable receiver may or may not process the augmentation information transmitted by MSAS, depending upon Pseudo Random Noise (PRN)-code settings in the receiver. MSAS uses PRN-codes (129 and 137) different from those for WAAS (135 and 138). If the receiver has PRN-code settings only for WAAS, it cannot process the information from MSAS. If you would like to know the PRN-code settings of your receiver, please contact the manufacturer of the receiver.

Q3.How much improvement of positioning accuracy will be gained when using the augmentation information transmitted by MSAS?

A3. MSAS signals achieve intended purpose and performance only if used by the airborne SBAS receiver conforming to TSO-C145a/146a. Please also note that non-aviation receivers using MSAS signals may NOT provide better positioning performance.The degree of accuracy improvement has not yet been determined. MSAS performance is to be ****yzed in the near future, following a required period of data collection. From simulations available so far, it is expected that MSAS can improve positioning accuracy down to a few meters.

http://www.kasc.go.jp/_english/msas_01.htm

Nicko
19th March 2009, 10:08 AM
additional info

http://www.nec.com/global/solutions/cns-atm/products/navigation/index.html#n03

http://www.environmental-studies.de/Precision_Farming/EGNOS_WAAS__E/3E.html

Albany Canucks
10th September 2010, 01:19 PM
So as it stands today, users in Australia should switch WAAS on their GPS receivers OFF, since it doesn't function here anyway, and the best we can get is the usual accuracy of between 5 and 15 meters?

Michael
10th September 2010, 02:15 PM
So as it stands today, users in Australia should switch WAAS on their GPS receivers OFF, since it doesn't function here anyway, and the best we can get is the usual accuracy of between 5 and 15 meters?
Yes

Treadly
10th September 2010, 03:02 PM
So as it stands today, users in Australia should switch WAAS on their GPS receivers OFF, since it doesn't function here anyway, and the best we can get is the usual accuracy of between 5 and 15 meters?

The "accuracy" as stated on the GPS doesn't mean that that is the best accuracy, it's actually the worst accuracy. The GPS is telling you where it thinks you are with the proviso that it could be up to between 5 and 15 metres out. But there is a chance that it could be spot on.

Bug's
10th September 2010, 07:12 PM
"Accuracy" stated by GPS means next to nothing, manufacturers imagination.

"Accuracy" stated by system is < 7m 95% of time

The Explorer
10th September 2010, 08:19 PM
snip
"Accuracy" stated by system is < 7m 95% of time

What "system" and under what circumstances?

Cheers
Greg

Bug's
11th September 2010, 08:00 AM
Global Positioning System (GPS)

Everyday circumstances wordwide dependent on minimum specified requirements.

Treadly
11th September 2010, 09:28 AM
What "system" and under what circumstances?

Cheers
Greg

On my Garmin GPS it has a reading that tells you the accuracy of the reading. For example, if it reads 7 metres, then it is telling you where you are, but could have an error of up to 7 metres.

Bug's
11th September 2010, 09:42 AM
On my Garmin GPS it has a reading that tells you the accuracy of the reading. For example, if it reads 7 metres, then it is telling you where you are, but could have an error of up to 7 metres.

Accuracy based on determination from a known fixed point. How then GPS receiver knows where it is in first place?

Oh wait you mean Estimated Position Error? Manufacturers imagination.